Donald Trump became the first president to address the National Rifle Association in over 30 years. That alone made news. But it was a statement about the 2020 presidential election that caught his audience off guard. Mr. Trump delivered the kind of raw meat NRA members expected. His stance on guns remains undeniable. But then the president named the Democrat he believes he is most likely to face in his re-election bid in four years.

Trump said he thinks his 2020 presidential opponent will be liberal Senator Elizabeth Warren, of Massachusetts. In his speech, he referred to the senator by a nickname he gave her last year – a name many say is racially insensitive.

“It may be Pocahontas,” Trump said before the Atlanta crowd, noting that Ms. Warren is not a big fan of the NRA.

Warren has been discussed as a potential 2020 candidate before and was considered to be one of the most effective foils for Mr. Trump in the 2016 campaign. Before Hillary Clinton even won the Democratic nomination last year, Ms. Warren had stood up to make a name for herself as a tough opponent to Mr. Trump.

She has not warmed to the man who has become her president since. The former Harvard professor who has positioned herself largely as an anti-Wall Street and pro-banking regulations senator frequently characterizes Mr. Trump as a billionaire false populist who is taking advantage of working class voters.

When asked, Warren has generally ducked questions of a potential 2020 run, which has fueled some speculation that she may have plans to announce a bid after her re-election to the Senate. She also recently published a new book. That book, titled This Fight Is Our Fight: The Battle to Save America’s Middle Class, has led some to wonder if she intends on using it as a launching pad for a White House bid.

Mr. Trump, who is well known for coming up with nicknames for his political foes on the campaign trail, started calling Warren “Pocahontas” after he learned that she has some Native American heritage. While her heritage has been disputed since then, Ms. Warren contends that she has never furthered her career by using that heritage to her advantage in any way.